DE-13-002 -- Distribution Map of Multi-Walled Carbon Nanotubes in a Refrigerant and Oil Mixture within a 2.5 Ton (8.8 kW) Unitary Air-Conditioner PDF

In recent years, nanoparticles have received considerableattention as a potential additive to heat transfer fluids (e.g.,refrigerant) in order to increase their overall heat transfercapabilities. The potential of carbon nanotubes (CNT) tocirculate throughout a vapor compression air-conditioningsystem was experimentally investigated in this research. Sixgrams of CNT were added to the R-410A and polyol ester oilused by a 2.5 ton (8.79 kW) unitary air-conditioning system,and then continuously operated for 168 hours. A distributionmap of CNT was developed based on post-experiment destructiveinspection of the system. For the 92.6 grains (6 g) initiallyplaced into the compressor, approximately 38.6 grains (2.5 g)were recovered from inside the compressor, leaving 54 grains(3.5 g) distributed elsewhere throughout the system. A portionof the CNT found were in the process of flowing with the refrigerantand oil (18.5 gr [1.2 g]) outside the compressor after the168 hour test), but the majority had become strongly adheredto the interior surface walls. The location of the heaviest foulingwas found in the first two to three feet (0.61–0.91 m) oftubing in each aluminum condenser circuit and a total of25.5 grains (1.65 g) throughout the condenser.